1. Field of the Invention
This invention relates generally to the field of prime surface heat exchangers for high temperature gases and, more particularly, to stainless steel plating for construction of a prime surface heat exchanger with a braze cladding on only one surface of the plate exposed to the coolant.
2. Description of the Related Art
A common method of manufacture for heat exchangers involves brazing. In manufacturing high temperature heat exchangers, such as gas coolers for exhaust gas recirculation (EGR) applications, the currently available options for brazing material are both costly and difficult to work with. An exhaust gas to water jacket coolant EGR cooler can be expected to see inlet gas temperatures in excess of 1200° F. This temperature will quickly oxidize standard copper based brazing alloys used in heat exchanger construction thereby causing premature failure. The plates used in the heat exchanger itself have hot exhaust gas on one side, and coolant on the other, keeping the actual metal temperature under 300° F.
It is therefore desirable to use plates clad with braze alloy on one side only, exposing the braze alloy to the coolant, and the stainless steel base metal to the hot gas.